Helmets, such as ballistic helmets, commonly include retention systems, which may include retention straps or harnesses, for securing the helmet onto a wearer's head. The retention straps may be affixed to the helmet with screws or grommets that pass through holes machined or otherwise formed into the helmet. As a number of helmets are formed of composites, including ballistic composites, it may be very difficult to machine a hole through the helmet to secure the hardware that affixes the retention straps to the helmet. The holes may also form stress concentrations, regardless of the material the helmet is formed of, reducing the overall ballistic protection of the helmet. Further, hardware, such as grommets or screws, may cause additional damage to the wearer when the helmet is hit by a projectile or other object.